A liquid crystal display (LCD) has advantages of low radiation, small size and low power consumption and so on, and is applicable to electronic products such as a notebook computer, a flat panel TV or a mobile phone and the like widely. Typically, the liquid crystal display comprises a pixel array, a data driving circuit and a strobe driving circuit. When the liquid crystal display displays, the data driving circuit can input the input display data to data lines of a liquid crystal panel, and the strobe driving circuit converts the input clock signal into a voltage that controls turn-on/turn-off of pixels in the pixel array via a shift register, and applies the voltage to strobe lines of the liquid crystal panel progressively.
In order to further reduce production cost of liquid crystal display products, the existing strobe driving circuit is always designed by using a Gate Driver on Array (GOA), wherein a thin film transistor (TFT) strobe switch circuit is integrated on the array substrate of the display panel to form a scanning drive of the display panel. In this way, it not only reduces cost of products in two aspects of material cost and manufacturing process, but also makes the display panel has an aesthetic design.
In general, in the shift register of the GOA technique-based strobe driving circuit, clock signals always appear in pairs, for example, including a clock signal CLK and a reverse clock signal CLKB. The specific number of pairs may be one, two or three etc., i.e., a configuration having two clock signals, a configuration having four clock signals, and a configuration having six clock signals and so on. Generally, the shift register is disposed individually with a pulling-down control unit configured to control pulling-down of the shift register. After a puling-up unit of the shift register pulls up an output signal level of the shift register in accordance with a potential of a pulling-up control node, the pulling-down control unit controls and executes the pulling-down operation. The pulling-down control unit generally comprises a plurality of TFTs. In order to pull up and pull down the output signal level of the shift register, a plurality of TFTs are also necessary. The large number of TFTs cause wiring in the shift register become complicated. Therefore, it is desired to be capable of reducing the number of elements (in particular TFTs) in the shift register and simplifying the design of wiring of the shift register.